Wednesday, December 16, 2015

Iron supplements could help avoid anemia and mild cognitive impairment

In a large population-based study of
randomly selected participants in Germany, researchers found that participants
with anemia showed lower performances in verbal memory and executive functions.
Furthermore, mild cognitive impairment (MCI) occurred almost twice more often
in participants diagnosed with anemia.

Anemia is a condition
that develops when your blood lacks enough healthy red blood cells
or hemoglobin.
Hemoglobin is a main part of red blood cells
and binds oxygen. If you have too few or abnormal red blood cells, or your
hemoglobin is abnormal or low, the cells in your body will not get enough
oxygen. Older adults also may have a greater risk of developing anemia because
of poor diet and other medical conditions. Iron-deficiency anemia, the most
common type, is very treatable with diet changes and iron
supplements.

The study is published in the Journal
of Alzheimer's Disease.

Because dementia is the end stage of
many years of accumulation of pathological changes in the brain, researchers
focus on early stages of cognitive impairment. MCI represents an intermediate
and possibly modifiable stage between normal cognitive aging and dementia.
Although persons with MCI have an increased risk of developing dementia or
Alzheimer's disease (AD), they can also remain stable for many years or even
revert to a cognitively normal state over time. This modifiable characteristic
makes the concept of MCI a promising target in the prevention of dementia.

What criteria determine MCI? The
following four criteria were used to diagnose MCI:

First, participants have to
report a decline in cognitive performance over the past two years. Second, the
participants have to show a cognitive impairment in objective cognitive tasks
that is greater than one would expect taking their age and education into
consideration. Third, this impairment is not as pronounced as in demented
individuals since persons with MCI can perform normal daily living activities
or are only slightly impaired in carrying out complex instrumental functions.
Fourth, the cognitive impairment is insufficient to fulfil criteria for
dementia.

The concept of MCI distinguishes
between amnestic MCI (aMCI) and non-amnestic MCI (naMCI). In the former,
impairment in the memory domain is evident, most likely reflecting AD
pathology. In the latter, impairment in non-memory domains is present, mainly
reflecting vascular pathology but also frontotemporal dementia or dementia with
Lewy bodies.

The Heinz Nixdorf Recall (Risk
Factors, Evaluation of Coronary Calcium and Lifestyle) study is an observational,
population-based, prospective study that examined 4,814 participants (50% men)
between 2000 and 2003 in the metropolitan Ruhr Area. After five years, a second
examination was conducted with 92% of the participants taking part. The
publication reports cross-sectional results of the second examination.

First, 163 participants with anemia
and 3,870 participants without anemia were included to compare the performance
in all cognitive subtests. Interestingly, anemic participants showed more
pronounced cardiovascular risk profiles and lower cognitive performance in all
administered cognitive subtests. After adjusting for age, anemic participants
showed a significantly lower performance specifically in the immediate recall
task and the verbal fluency task.

Second, 579 participants diagnosed
with MCI (299 participants with aMCI and 280 with naMCI) and 1,438 cognitively
normal participants were included to compare the frequency of MCI and MCI
subtype diagnosis in anemic and non-anemic participants. MCI occurred almost
twice more often in anemic than in non-anemic participants. Similar results
were found for MCI subtypes, indicating that low hemoglobin level may
contribute to cognitive impairment via different pathways.

These results suggest that anemia is
associated with an increased risk of MCI independent of traditional
cardiovascular risk factors. The association of anemia and MCI has important
clinical relevance because -depending on etiology- anemia can be treated
effectively. This might provide means to prevent or delay cognitive decline.